Is there an existing issue for this?

• I have searched the existing issues

Current behaviour

See inline discussion at #26467 (comment)

@whitslack:

Consider the case where I am paying someone on chain under the stipulation that they will eat the mining fee. (Thus, I specify their address in subtractfeefrom when I'm constructing my transaction.) Later, they tell me that they can't wait for confirmation any longer and need an urgent fee bump. If I naïvely specify their output as the reduce_output, I may end up paying them much more than I intended to if I only have large UTxOs in my wallet.

Expected behaviour

Not sure.

Improving the docs is one option, but this behaviour seem quite counter intuitive.

My own suggestion:

Should we disable the adding of new inputs when reduce_output is set? If someone really intends to do that, they should probably use outputs.

Steps to reproduce

Haven't tried.

Relevant log output

No response

How did you obtain Bitcoin Core

Compiled from source

What version of Bitcoin Core are you using?

Master after #26467

Operating system and version

Any

Machine specifications

No response